50s vintage watch mens Certina Calendar ref 79312 automatic 28-451 gold cap

Case:
o   Gold capped with stainless steel back with marks all over ref. 79312 serial 3.249.162
o   Fine condition with strong geometry
o   36mm without crown / 45mm lug to lug  / 11mm thickness / 19mm lug width
o  Original crown

Movement:
o    Mechanical automatic cal 28-451 -  serviced by watchmaker on October 2025
(movement was disassembled, washed, lubricated)

Dial and Hands:
    o  Black dialwith golden index’s

Bracelet Material: 
  o New 19mm black leather, with generic golden buckle

Conclusion / Condition: 
A rare watch in good working condition from 1957, its elegance and finesse somewhat similar to the Omega Constellation line...

please see photos as they are part of the description.
No box or pappers, no water proof test, sold as is, any question feel free for ask...
Keep in mind that it is a vintage watch, it is normal to be 1/2 minute early or late
wrist-treasure